Procedure Table Storage Spec

[Latrasis]

We need to update the procedure table spec in #113.

[Latrasis]

Here's a summary of what's left to discuss:

• KeyIndex in Procedure Heap for O(1) insert/delete
• Kernel Instance / Library Definitions ( Seperate Kernel Logic into Library #63)
• Procedure Protection (Handle Procedure Destroy Attacks #115 )
• Increase Kernel Storage Prefix

[JakeOShannessy]

Move kernel storage to high-values (i.e. 0xffffffff).

[JakeOShannessy]

I've called the solution to procedure protection an "execution guard", and specified it as follows:

0x00: PUSH 0xffffffff0200...00 // Push kernel addr. location
0x21: SLOAD     // Load value to the stack
0x22: PUSH 0x2a // Load value to the stack
0x24: JUMPI     // Jump if kernel address non-zero
0x25: PUSH1 0x00 // Revert data size
0x27: PUSH1 0x00 // Revert data location
0x29: REVERT    // Revert because we are not a kernel
0x2a: JUMPDEST  // Destination to jump over

We might be able to remove those last two pushes, but I think that relies on undefined behaviour, so I think we shouldn't, especially as they aren't executed in the normal path.

[Latrasis]

@JakeOShannessy: I've made additional comments. Should be ready to merge afterwards.

[Latrasis]

Closing on #113